Fluid handling – Self-proportioning or correlating systems – Self-controlled branched flow systems
Reexamination Certificate
2000-01-20
2001-06-05
Hepperle, Stephen M. (Department: 3753)
Fluid handling
Self-proportioning or correlating systems
Self-controlled branched flow systems
C137S109000, C137S119030, C137S119050, C137S565330, C137S597000, C417S286000
Reexamination Certificate
active
06240949
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a three-way diverter valve, and more particularly, the present invention is directed to a three-way diverter valve which utilizes a solenoid in combination with a poppet.
BACKGROUND OF THE INVENTION
Devices such as cranes, have lateral outriggers with hydraulically projected pads which engage the ground to keep the crane stable while in use. Since the hydraulically projected pads require pumped hydraulic fluid only when being projected, there is hydraulic pumping capacity available for other uses after the crane, or other device, has been stabilized.
In cranes, it is proposed to use a diverter valve for selecting two functions the flows of which are combined to achieve maximum operating efficiency of a single winching function. This requires a solenoid operated, three-way valve which in a satisfactory configuration is currently not available. Current three-way valves malfunction because they utilize a solenoid spool which is subject to Bernoulli forces.
In presently available three-way spool valves, malfunctions occur as certain flow limits are passed, during high pressure conditions, or when high flow rates combine with high pressure conditions. In order to cope with this phenomenon, attempts have been made to increase the size of three-way valves. However, as size increases, design difficulties are encountered because it is necessary to match available solenoid forces against a required spring force to overcome Bernoulli forces. Bernoulli forces occur when two negative flows caused by the velocity of hydraulic fluid over flow surface areas of the spool combine, creating a negative force which tends to close the valve spool. One approach to solving this problem has been to use solenoid-operated, four-way valves to perform the function of three-way valves. However, since four-way valves are of essentially the same design configuration as three-way valves, they also fail under Bernoulli forces. Another approach has been to use various combinations of bi-directional, two-way valves, but this requires two separate solenoid valves and it is preferable to utilize only a single solenoid valve. Use of two-way valves in combination is also not necessarily desirable because the two-way valves can sometimes stall or restrict flow if certain differential pressure conditions are not met.
SUMMARY OF THE INVENTION
The present invention is directed to a solenoid operated diverter valve comprising a valve body having a first inlet, a second inlet, a first outlet and a second outlet. A first passageway connects the first inlet and first outlet to the second inlet. A solenoid valve is disposed in a second passageway between the second inlet and the second outlet, the solenoid valve having a first mode in which hydraulic fluid flows through the solenoid valve to the second outlet and a second mode in which the solenoid valve blocks passage of fluid from the second inlet to the second outlet. A check valve is disposed between the first passageway and the second passageway. The check valve has a first end urged to close the first passageway to fluid from the second inlet and a second end connected to the second passageway for receiving pressurized hydraulic fluid from the second passageway to keep the check valve closed when the solenoid valve is in the first mode. The first end of the solenoid valve has fluid pressure from the first passageway applied thereagainst to open the second inlet to the first passageway when flow through the second passageway is blocked by the solenoid valve, wherein fluid from the second inlet flows into the first passageway and out of the first outlet rather than through the second outlet.
In a further aspect of the invention, the solenoid operated diverter valve includes a valve element which is closed when the solenoid valve is energized and is open when the solenoid valve is de-energized.
In a further aspect of the invention, the poppet of the solenoid operated diverter valve includes a spring arrangement for urging the poppet to close the first passageway to fluid from the second inlet.
In a further aspect of the invention, the poppet valve comprises a poppet element within a poppet housing and the spring arrangement comprises one spring urging the poppet housing to close the first passageway and another spring between the poppet housing and poppet element additionally urging the poppet element to close the first passageway.
In still a further aspect of the invention, the first inlet of the solenoid operated diverter valve is adapted to be connected to a first pump and the second inlet is adapted to be connected to a second pump.
In still a further aspect of the invention the solenoid diverter valve is used with a crane, the first pump providing system hydraulic pressure and the second pump providing pressure for a crane stabilizing system.
REFERENCES:
patent: 2601868 (1952-07-01), Gill
patent: 2761388 (1956-09-01), Peterson
patent: 3858607 (1975-01-01), Baker
patent: 4073140 (1978-02-01), Lang et al.
patent: 4169491 (1979-10-01), Bajka
patent: 5445182 (1995-08-01), Sturman et al.
Hepperle Stephen M.
Millen White Zelano & Branigan P.C.
Parker-Hannifin Corporation
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